Disclaimer option in settings appears to have no effect

**Describe the bug**
In GN2 there used to be an option to display a disclaimer (constraints on usage of the data) when downloading an uploaded file. The setting to switch this on is still available in Settings, but doesn't appear to have any effect.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to Admin console / Settings
2. Under download service select 'Use geonetwork disclaimer and constraints service' instead of simple service (set to true and false respectively)
3. Create a new 19139 or 19115-3:2018 metadata record, upload and link a file, add some constraints and publish the record
4. Log out and download the uploaded file
5. The file just downloads - no disclaimer/constraints are displayed

**Expected behavior**
When attempting to download the file a disclaimer is displayed which must be accepted before the file can be downloaded.

**Screenshots**


**Additional context**
tested in master branch

Start in Admin console / Settings by reproducing the download-service behavior with the disclaimer and simple service options, then follow the uploaded-file download flow. Done means the configured disclaimer and constraints are displayed and must be accepted before the file downloads, while the simple service continues to download directly.

Written by the indexing model from the issue text.